public class Node{
    public int value;
    public Node next;
    public Node{int data}{
        this.value=data;
    }
}

public Node reverseList(Node head){
    Node pre=null;
    Node next=null;
    while(head!=null){
        next=head.next;
        head.next=pre;
        pre=head;
        head=next;
    }
    return pre;
}